STRESS RESPONSES IN ALFALFA (MEDICAGO-SATIVA L) .6. DIFFERENTIAL RESPONSIVENESS OF CHALCONE SYNTHASE INDUCTION TO FUNGAL ELICITOR OR GLUTATHIONE IN ELECTROPORATED PROTOPLASTS
STRESS RESPONSES IN ALFALFA (MEDICAGO-SATIVA L) .6. DIFFERENTIAL RESPONSIVENESS OF CHALCONE SYNTHASE INDUCTION TO FUNGAL ELICITOR OR GLUTATHIONE IN ELECTROPORATED PROTOPLASTS
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DOI：
10.1104/pp.94.4.1802
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发表时间：
1990-12-01
期刊：
影响因子：
7.4
通讯作者：
DIXON, RA
中科院分区：
文献类型：
--
作者：
CHOUDHARY, AD;LAMB, CJ;DIXON, RA
以紫花苜蓿（Medicago sativa L.）通过增加内源性查耳酮合酶（CHS）活性对真菌诱导子（FE）处理作出反应，但对还原型谷胱甘肽（GSH）无反应。 原生质体预暴露于聚乙二醇和电穿孔导致对GSH的强烈反应，但对FE的反应性变化不大。 原生质体从悬浮培养已超过12次失去了对GSH的反应，但不FE，通过测量含有连接到细菌氯霉素乙酰转移酶（CAT）报告基因的豆CHS启动子的嵌合基因的表达进行评估。 在原生质体中，假定的顺式作用CHS启动子序列已coelectroporated在反式与完整的CHS启动子-CAT结构，CAT表达的程度取决于所使用的激发子（FE或GSH），年龄（传代培养的次数）的细胞从其中分离的原生质体，和coelectroporated CHS启动子序列的性质。 例如，CHS启动子的-326至-141的区域在与CAT构建体共电穿孔到从新启动的细胞悬浮液分离的未引发的原生质体中时表现为反式激活因子，但在FE存在下，相同区域在相同的原生质体中充当反式沉默子。 这种沉默剂活性在GSH处理的原生质体中大大降低。 结果表明，有不同的信号转导途径的启发CHS转录铁和GSH，其中涉及以前确定的顺式元件在CHS启动子。
Protoplasts derived from cell suspensions of alfalfa (Medicago sativa L.) responded to treatment with fungal elicitor (FE) by an increase in endogenous chalcone synthase (CHS) activity but were unresponsive to reduced glutathione (GSH). Preexposure of protoplasts to polyethylene glycol and electroporation resulted in strong responsiveness to GSH but little change in responsiveness to FE. Protoplasts from suspension cultures which had been subcultured more than 12 times lost responsiveness to GSH, but not FE, as assessed by measuring expression of a chimeric gene containing a bean CHS promoter linked to a bacterial chloramphenicol acetyltransferase (CAT) reporter gene. In protoplasts in which putative cis-acting CHS promoter sequences had been coelectroporated in trans with the intact CHS promoter-CAT construct, the extent of CAT expression depended upon the elicitor used (FE or GSH), the age (number of times subcultured) of the cells from which the protoplasts were isolated, and the nature of the coelectroporated CHS promoter sequence. For example, a region of the CHS promoter from -326 to -141 behaved as a trans-activator when coelectroporated with the CAT construct into unelicited protoplasts isolated from newly initiated cell suspensions, but the same region acted as a trans-silencer in the same protoplasts in the presence of FE. This silencer activity was much reduced in GSH-treated protoplasts. The results suggest that there are differences in the signal transduction pathways for elicitation of CHS transcription by Fe and GSH, which involve previously identified cis-elements in the CHS promoter.